Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Research Article Karhunen-Lo` ve-Based Reduced-Complexity Representation e of the Mixed-Density Messages in SPA on Factor Graph and Its Impact on BER | Hindawi Publishing Corporation EURASIP Journal on Wireless Communications and Networking Volume 2010 Article ID 574607 11 pages doi 2010 574607 Research Article Karhunen-Loeve-Based Reduced-Complexity Representation of the Mixed-Density Messages in SPA on Factor Graph and Its Impact on BER Pavel Prochazka and Jan Sykora Department of Radio Engineering Faculty of Electrical Engineering Czech Technical University in Prague Technicka 2 16627 Praha 6 Czech Republic Correspondence should be addressed to Pavel Prochazka prochp10@ Received 26 March 2010 Revised 2 September 2010 Accepted 30 December 2010 Academic Editor Monica Nicoli Copyright 2010 P. Prochazka and J. Sykora. This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited. The sum product algorithm on factor graphs FG SPA is a widely used tool to solve various problems in a wide area of fields. A representation of generally-shaped continuously valued messages in the FG SPA is commonly solved by a proper parameterization of the messages. Obtaining such a proper parameterization is however a crucial problem in general. The paper introduces a systematic procedure for obtaining a scalar message representation with well-defined fidelity criterion in a general FG SPA. The procedure utilizes a stochastic nature of the messages as they evolve during the FG SPA processing. A Karhunen-Loeve Transform KLT is used to find a generic canonical message representation which exploits the message stochastic behavior with mean square error MSE fidelity criterion. We demonstrate the procedure on a range of scenarios including mixture-messages a digital modulation in phase parametric channel . The proposed systematic procedure achieves equal results as the Fourier parameterization developed especially for this particular class of scenarios. 1. Introduction A factor
